How to Raise Hot Tub pH?

For most people, a hot tub is simply a place to relax in warm, bubbling and massaging water. And for most people, that’s all that’s necessary – to simply enjoy the experience. However, someone needs to be responsible for maintaining the hot tub, keeping the water clean and crystal clear as well as ensuring the water chemistry is balanced. A big part of keeping the water chemistry in line is knowing how to raise hot tub pH. In this article, we go over what pH means and how to regulate it.

What Does pH Mean?

pH is the measure of the acidity or basicity of a solution. The pH scale runs from 1, which is the most acidic to 14, which is the most basic. 7, being in the middle of the scale, is neutral. For a hot tub, the pH level that you’re trying to achieve is between 7.4 and 7.6, or slightly basic.

Low pH

If the pH of your hot tub water is below 7.4, it’s getting close to being acidic and it’s harder for your sanitizer to work properly. Low pH causes sanitizers to break down more quickly and will cause you to use more than usual. If your sanitizer levels are off, this could allow the proliferation of bacteria and other contaminants. The water may irritate the bathers’ skin and cause a burning sensation of the nose and eyes. Low pH levels may also be responsible for causing corrosion of the hot tub’s metal parts.

High pH

When the pH of the hot tub water is above 7.6, the water is basic. You’ll end up with some of the same problems found with a low pH measurement, such as having a tough time keeping your sanitizer levels in check and irritation of the skin, nose, and eyes. A high pH level can also cause calcium to precipitate out of the water resulting in scaling, lime buildup and possible clogging of your plumbing. You may also find that your water goes cloudy and dull.

Total Alkalinity

The first step to getting your pH levels in check is to measure the total alkalinity of the water. This is because total alkalinity measures the ability of the water to neutralize acids – an important property if you’re trying to adjust the amount of acid in the water. Total alkalinity should be between 125 to 150 ppm. You measure total alkalinity using water test strips or by adding a reagent to a sample of water and comparing the resulting colours to a test chart. Depending on the total alkalinity of the water you could add total alkalinity increaser or decreaser.

Testing the ph Level

Once your total alkalinity is in the correct range, you can test the pH level of your water. Again, you could use water test strips or a water test kit to find out what the pH currently is. To do this properly you should run the hot tub water pump for at least 10 minutes to ensure the water is well mixed before turning the pump off again. When taking a sample of the water it should be done about 30 centimetres below the water surface. Hold the sample container upside down with your thumb over the opening and dip it into the water to about elbow length before removing your thumb, turning the container over and allowing it to fill with water.

If you’re using water test strips simply dip one into the water sample and check the resulting colour against the chart on the container to ascertain the pH. If you’re using a water testing kit, add the recommended amount of reagent to the water sample and check the resulting colour against the test chart to find the pH.

Raising the pH Level

If the pH level is low, you’ll need to add soda ash to the water to bring it up. Compare the amount of water in your hot tub with the water’s current pH level on the soda ash container chart to determine the amount of soda ash you’ll need to add. Measure the proper amount, turn the water pump back on and add the soda ash to the water over the deepest area of the tub. After the tub has run for an hour you can test the water again to see if more soda ash needs to be added.

About the Author

Scott Bland has been in the leisure industry for nearly 20 years.  As a sales manager in the leisure industry he knows hot tubs inside and out.  Right now, he works sales while writing about hot tubs, pools and spas on his blog,